


Casus belli

by NikitaHawkeye



Category: Marvel 616, Miraculous Ladybug
Genre: Civil War AU, F/M, Gen, post-reveal, sort of
Language: English
Status: In-Progress
Published: 2016-04-05
Updated: 2016-06-18
Packaged: 2018-05-26 21:17:05
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence, No Archive Warnings Apply
Chapters: 3
Words: 3,899
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6256231
Author URL: https://archiveofourown.org/users/NikitaHawkeye/pseuds/NikitaHawkeye
Summary: <blockquote class="userstuff">
              <p>In which the end was only the beginning. </p><p>Three years ago, the United States government deemed all superhumans "possible weapons of human destruction," and mandated all of them to register and operate only under the law. Various governments around the world agreed and enacted the same law, including France. </p><p>Three years ago, the heroes of Paris managed to bring down their arch enemy. The catch, however, was the one thing they didn't count on.</p><p>Hawkmoth went down, only he brought Chat Noir with him.</p>
            </blockquote>





	1. Chapter 1

**D.G.S.E. EYES ONLY**

**MISSING PERSONS CASE**

**RE: AGENT MARINETTE DUPAIN-CHENG A.K.A LADYBUG**

**TRANSCRIPT: DIRECTION GÉNÉRALE DE LA SÉCURITÉ EXTÉRIEURE, DIRECTION DES OPERATIONS**

**DDO:** State your name and position.

 **Ladybug:** [exhale] Marinette Dupain-Cheng, a CPES agent under the Action Division.

 

 **DDO:** Very well, Agent Cheng. What was your role in the retrieval mission two weeks ago?

 **Ladybug:** Agent Maurice, my Agent-in-Charge, assigned me as the Task Force Leader for this assignment.

 

 **DDO:** This assignment, what was the nature of it?

 **Ladybug:** [pause] I don’t think I’m allowed to disclose the—

 

 **DDO:** As the Director of Operations, you are very well obliged to disclose to me every detail of the assignment in question, Agent Cheng.

 **Ladybug:** …Roughly three weeks ago, an anonymous tipper sent information about suspicious activities in Bezonvaux. The Action Division had reason to believe there were rogue German soldiers inhabiting the area, so they arranged a team to be deployed to the commune. The assignment was rather straightforward: get in, sweep the area, investigate, apprehend any suspicious person on sight, get out.

 

 **DDO:** If it was a rather simple assignment, why send an agent of your calibre?

 **Ladybug:** With all due respect, Director, I said straightforward, not simple.

* * *

 

_6 months ago…_

**_Le Château des Lumiéres_ **

**_Saint Blimont 80960, Picardie, France_ **

**_50°07'15" N 01°34'26" E_ **

**_0421 HRS_ **

“All units, check in.”

_“Unit One, standing and ready. We have full visual on the entrance. Over.”_

_“High-ground One, adjacent buildings on 3 o’clock covered. Over.”_

_“Unit Two, full visual on the rear, over.”_

_Such irony,_ Marinette thought wryly as she adjusted her body holster. Reports from other units poured in as her team suited up inside a cramped armor van, five blocks away from the location. Three more vans pulled up, indicating the arrival of more back-up units.

Operation Eurydice is a manhunt mission composed of four ground units and three sniper units, all from the most elite DGSE squads. Sending the best black-ops soldiers in France to this particular mission can only mean one thing: the country is facing yet another grave threat. "Grave threats" nowadays did not mean "military terrorists" and "sleeper spies" anymore. "Grave threats" nowadays usually meant "alien invasions" and "extraterrestrial terrorists" and "biotechnologically-enhanced weapons," and it all started when a Nordic god fell from the sky a few years back.

"Grave threat," in this particular case, is a ghost of a mercenary that terrorized military operations, sabotaged political summits, and participated in wars without allegiance. Same shit, different day, so what's got the government's granny underpants in a twist?

The answer is simple: this mercenary has left a high amount of damage that no man could ever cause, physically and synthetically. He left serious destruction in his wake, and the evidence were too _molten_ to examine. Molten, but not by heat.

This would have been just another job for her. It's not like she was a stranger to the supernatural phenomena; hell, she was a transforming superhero with superhuman strength and rectifying power. America had a group of enhanced beings to fight off the Chitauri and the sentient robots; France had her and her partner. She was no greener, and it should have just been another job.

Until she opened the mission dossier.

The file was short but succinct, but contained nothing that she didn't already know: an unnamed mercenary on the loose had terrorized Operation Dorca , sabotaged a presidential summit in South-East Asia, and was seen opening fire in a civil war in Middle East.

What knocked the air out of her was the attached photograph below the file. It was grainy, and the shot was out of focus, but she instantly knew who she was looking at.

The blonde hair, the green eyes, the perfect face. 

The Agrestes' mysterious disappearance caused an uproar among bewildered fans. Gabriel Agreste abandoning his fashion empire just didn't make sense; the winter collection from his line was just announced, and future collaborations with other designers were just confirmed by his assistant. A sudden out-of-town trip with his son was bizarre at that time of the year. The supposed trip lasted into days, months, _years_... and no one heard from them.

Rumors started to circulate the country. Are they secretly running away from a huge debt? Is the Italian mafia after the illustruous family? Were they abducted by unknown forces? Father and son got tired of the luxurious life and decided to settle in the countryside? 

What no one noticed was this: _the Akuma attacks ceased the same day the Agrestes disappeared_. 

Marinette knew exactly what happened, and that was the reason why her head was reeling and her knees were shaking on the spot. Whatever shock she felt must have manifested on her suddenly pale face, and she had to excuse herself because the urge to throw up was too strong then. 

That was three weeks ago, right before she was able to pull herself together and think objectively. 

 _Right. Objectively._  “Secure line three.”

“Three secured,” her partner chimed from beside her, his lopsided grin holding a lit cigarette in its corner.

Raoul Gillet is a man ten years her senior, a seasoned soldier with 19 successful missions under his belt, and Marinette was so close to trusting him with her life.

Forming another partnership with someone after everything that happened just didn't sit well with her. She was so against the idea, to the point that she almost handed her resignation letter to the higher-ups. Gillet, however, chose to stop being mum about the whole thing. 

_"Look, kid. I don't really understand why you're so against the idea of having someone watch your back, and I will not even pretend to understand. But Paris needs you, and while we all know that you can very well handle yourself,  you will always need a partner whom you can count on at all times."_

_And that was the start of a very efficient partnership._

The smoking habit, however, she could never tolerate.

Marinette covered the mini microphone with her finger. “Knock that shit off, Gillet.”

Gillet puffed and pulled the stick out of his mouth, then squashed it under his boot. “I’m done, anyway.”

She shook her head and pulled out the binoculars from her utility belt, then zoomed in on the building’s façade.

Chateau Lumiere, contrary to popular belief, is not a single building. There are three Chateau Lumieres all over France, and the intel they received had pointed them to the guest house, the one owned by people who trusted the good of mankind too much to hire anyone to guard their grand property.

 _Probably not the best idea,_ she thought, because uninhabited spaces invite curious souls, ghosts, companies who liked to take advantage of free working spaces for their clandestine operations, or in this case, war criminals who are possibly former masked heroes.

Like _him_ , who seemed to somehow survive the incident from three years ago.

_…Which also happened in a grand mansion like this, a mansion she would never forget—_

Marinette promptly put away the binoculars and unclenched her fists.

“What’s the matter, Cheng? Don’t tell me you’re having cold feet—“

“It’s nothing,” she snapped and pressed the earpiece again, “all units, prepare to move in.”

* * *

 

The lobby of the mansion was a reminiscent of that one from a horror game she used to play with her papa: a grand staircase greeted them upon opening the antique wooden door, a round crystal chandelier adorned the main ceiling, and an expensive but old red carpet covered the floor and the steps of the staircase.

A shiver crawled down her spine as she took in the scene in front of her.

“Unit One, we’re going to investigate the west wing. Stay on our six,” she commanded, her voice slightly above a whisper. She motioned towards the wooden door on the left side of the staircase. Gillet followed suit, their combat boots barely making noises against the carpet.

Marinette reached out to twist the knob, and then pushed, the slight creaking of the door making her cringe…

…and the door led to the dining area, an enormous room yet again adorned by another intricate crystal chandelier. The antique wooden table was surrounded by matching twenty-four wooden chintz chairs, all neatly arranged, with no accumulation of dust in sight–

_Wait, what?_

She quickly wiped the table with her fingers, confusion and anxiety coiling in her chest. She rubbed her thumb and middle finger together, dreadfully confirming that yes, these things have been recently cleaned, which could only mean one thing.

The mansion is not empty. As to who currently inhabits it, they’re yet to find out.

It didn't take long to answer the million-dollar question.

 _“Boss,”_ her earpiece crackled, seven minutes after she entered the hallway that connects the kitchen to the guest rooms, " _This is High-ground Two. Thermal sensors detect activity in the southwest room of the west wing.”_

_“This is Unit Two, confirming thermal activity in the west wing—“_

_"—Unit Three, Beekepers on the rear—"_

_“Shit, confirmed sight of Beekepers! Go, go—“_

Marinette and Gillet broke on a sprint, all plans of stealth thrown in the wind. “Where are you? Talk to me!”


	2. Chapter 2

Marinette and Gillet pumped more energy into their legs, the southwest room suddenly seemed so far away as panicked reports from all units flooded the radio. ”Beekepers? That’s impossible. The Avengers have no business operating in France, let alone in an abandoned mansion!”

Gillet kept up and replied, slightly out of breath, ”You're right. If they are, our government would have been informed a long time ago."

He was only half-right, of course. They both knew the complications of infiltration. They would have not questioned it, of course, if it were just another intelligence agency. But if the Avengers were involved, it's usually something concerning global safety (or danger, more often than not), and the French government had every right to know whether some sort of galactic stone or celestial beings have taken refuge in one of its luxurious places. 

They rounded a corner and took turns in cursing when they heard gunshots from different directions. _"This is Unit Four, we're receiving fire from hostile forces—"_

_"Holy shit, those are high-powered shit right there—"_

_Of course they're armed, possibly with weapons they have never seen in their entire life._ Marinette barked commands in her radio as she frantically dashed. "Move! _Move now!"_

Strings of curses fell out of Gillet's mouth as they encountered another labyrinthine corridor, but Marinette have the blueprint of the mansion burned in her brain, so he grabbed his sweat-greased arm and ran to the emergency stairs on their right. "It's faster this way! Unit One, stay on our trail!"

The emergency exit led to the mansion's garden, and Marinette took a sharp turn to the right and busted through the first door they saw. 

The door opened to a gunfight between Unit Two and rougly ten Beekeepers, all armed with high-caliber weaponry. Gillet fired two rounds straight to the nearest Beekeeper's chest, and the soldier want down in an instant. Marinette resorted to tackling down three soldiers with one sweep of her yo-yo, using them as platform for jumping the other two on the other side of the room. With the string of her yo-yo around the guy's neck, she spun, her foot sweeping the other guy's head, effectively knocking him out. Using the string as a garrote, she pulled, and the guy went down in under a minute.

_If they're shooting at you, they're bad._

After turning around and seeing that most Beekeepers have been taken care of, she knelt to help a Unit Two soldier to his feet. "Are you alright?"

The soldier dusted off and winced, grabbing a bloody shoulder, as if preventing more blood to ooze out. He threw a weak grin and replied. "Don't worry, boss. I'll live."

Marinette nodded and motioned for the medics to come in. She turned to the rest of the team. "Unit One, go ahead and assist Unit Three in the rear. Gillet and I will assist Unit Four. Go!"

* * *

 

The number of Beekeepers against Unit Four were greater, and if she didn't need to pull out the MAC 50 from her holster earlier, she had to waste two entire clips this time.

Her no-kill policy was often questioned by the higher-ups; through the years she had been methodically keeping off the 'dirty' deeds: she kept declining hit jobs, steered clear of honeypot missions, and avoided giving lethal shots to her opponent as possible. If her bosses have a problem with it, they could always discharge her. 

Her, Ladybug, former child superhero, now one of France's best black-ops agent.

Of course, she was not able to completely avoid taking lives. It was inevitable. Her first kill was accidental and she almost lost her mind weeping about it for months. 

She didn't cry because taking a life was hard; she cried at how easy it was to actually do it.

She wiped off the sweat that started to blur her vision using her sleeve, taking some of the red and black warpaint with it. It had been years since she traded her mask for a warpaint, but old habits die hard. Sometimes she felt like she's never going to get used to it.

She scoffed as a Beekeeper tried to sneak up on her, his glowing taser inches away from her face. She turned and twisted his arm, and the Beekeeper was electrocuted by his own taser in a matter of seconds. Using the same weapon, she took down three more soldiers, all the while waving it around and marveling at how handy it came. 

One more group of six Beekeepers entered the area, and Marinette started to grow impatient for some answers.

She stepped on the last Beekeeper's chest and whipped out a radio from her utility belt, angrily punching down buttons. "I need HQ to contact the Avengers and demand answers _—_ "

”Cheng, you’re thinking about the re-branded AIM. I think these are rogue soldiers, from Strucker’s era.” Gillet's calloused hand slightly gripped her arm, stopping her from hitting the dial button.

"Wait, re-branded? Strucker?"

Gillet brushed past her and motioned for her to follow, "The Avengers Idea Mechanics was a rebranding of the Advanced Idea Mechanics, a former Nazi scientific organization, founded by Baron von Strucker. An Avenger took over it with force and transformed it to the respectable scientific organization we know today."

Marinette opened her mouth to speak but the crackling of her earpiece cut her off. _"This is Unit Two, we confirm an underground entrance in the middle of the garden. It seems to be activated with some sort of keycard, over."_

She locked eyes with Gillet, and with an affirmative nod, she replied. "Copy that. We're en route."

* * *

 

Key-activated locks are laughably easier to open, and Marinette was silently thankful for the hazmat suits the Beekeepers wore which made it impossible for any of their bases to have biometric locks. 

She lifted the keycard she had looted from a Beekeeper (which she took down by a swift, solid drop kick to the nape) and tapped it on a sensor attached to the metal door. It emitted a long beep, and the red light turned into green. The metal door finally slid open.

The door opened to a flight of stairs going down into total darkness. She exhaled and clicked her Maglite open, and, with five units behind her back, and her MAC 50 leading the way, she stepped down the stairs and into nothing.

After what seemed an eternity, the spiraling steps finally came to an end. 

They were greeted by a cold, sterile room filled with advanced computers and cryogen tubes. It was straight out of a sci-fi horror film; deformed creatures that seemed to be breathing slept in the tubes. The glass jars on the walls were filled with different body parts, both animals' and humans'. The same type of fluid seemed to fill the tubes and jars, and the strong smell of antiseptic assaulted their nostrils. The main supercomputer was turned off, but she'd bet it contains advanced software and experimental results from the monstrosities right before them.

Rogue AIM soldiers were able to build an underground laboratory in Chateau Lumiere, right under their noses. 

The thought made Marinette sick in the stomach. She turned her flashlight to the other direction, fully intending to investigate more— 

_THUD._

A loud groan followed the sound, and Marinette turned to find the source—

—but a flash of yellow suddenly blocked her vision, and she quickly shone her light to the ceiling, only to find the swarm of Beekeepers dropping down from the ceiling like flies. 

**Notes for the Chapter:**

> For more information about AIM soldiers, please refer here: http://marvel.wikia.com/wiki/Advanced_Idea_Mechanics
> 
> The mansion’s layout was inspired by the Spencer Mansion from Resident Evil. The horror game referred by Marinette from the first chapter was, well, Resident Evil. Hahaha!
> 
> Please note that we will see a different Marinette here, very different from the Marinette we’re used to. But don’t worry! I will try to keep her in character as much as I can. Thanks for reading!


	3. Chapter 3

_They were waiting for them._

That was the last thing on her mind before she was dogpiled by five Beekeepers, all determined to subdue her with all their might, judging by the tightness of their grip and the loudness of the stun rod's crackle in front of her. 

People just keep on forgetting what the "superhero" title entailed, or perhaps just didn't know what an "enhanced human being" meant, and Marinette was just too glad to take advantage of the perks. With an extra effort, she pulled to her left, and a Beekeeper took the incoming blow. He limped uselessly, and she uses the opportunity to twist out of their holds. She threw the limping man at the stun-wielding Beekeeper and immediately planted her fist on the face of the one to her right. 

Now able to move freely, she quickly scanned the warzone and was reminded of being outnumbered. Using the wall as leverage, she ran and jumped the two Beekeepers on the left corner of the room, her roundhouse kick swiftly knocking the men down like dominoes. Had she been a second late, one of her men would have died with a bullet between his eyes. 

She was about to run to an incapacitated squad member when—

_—BOOM—_

—an explosion shook the ground, effectively knocking down on her knees.

_Shit, a grenade?_

Marinette swore loudly, partly out of disbelief, partly out of annoyance at herself. Of course these people would use grenades in this small room. Of course these people would be willing to sacrifice their own just to have the upper hand. _These men are Hydra, for Christ's sake!_

She tried to clamber to her feet, then felt someone pull her arm up. She was about to lash out when she realized it was Gillet, trying to help her to her feet while gingerly gripping his left leg, a rather large gash currently adorning it. She murmured a soft thanks and steadied herself, while trying to shake off the shock from the explosion. 

The smoke started to clear off, and she gasped at the scene before her. 

The laboratory, which used to look and smell erpristine and sterile, now reeked of blood and dirt, as wounded men lay everywhere, both allies and enemies alike. Some of her men were pinned down by huge chunks of debris, and, her gut churning, she ran, eager to help—

—ZING—

—she felt a blow to her shoulder bone, and quickly realized with horror that she had just been _shot._

_Oww..._

Marinette used to wonder whether the Ladybug suit was bulletproof or not. She often had the urge to go in front of the firing range and ask someone to _just test it out_ , but never had the chance to pull it off out of fear of being branded as insane. Shooting herself felt so wrong, so she never got to find out.

Until one, fateful day in Bordeaux.

A madman held a little girl hostage, an AK-47 in his right arm and the whimpering girl in his left. He demanded for the child's mother, and based on the madman's crazed rant, he and the mother were in the middle of a custody battle, and the man was on the verge of losing, so he had to resort to more forceful tactics. 

 _Bonehead move of the century_ , Ladybug thought as she tried to negotiate with the man. If he truly wanted to be with his daughter, why go out there and be the most idiotic hostage-taker in the history of Paris? Her impatience and irritation at the man urged her to take a tiny step forward, causing the man to open fire at her.

There were two things that she found out while she stumbled backwards: 1) she managed to make the man drop the child and his weapon in horror,  ending the drama, and 2) she was indeed, bulletproof. 

So why the hell is she bleeding on the floor like a wounded animal right now?

Fighting back a sob, she slowly turned to her right shoulder, and was greeted by an open wound emitting a purple haze.

_Is this... magic?_

She swooned, her hand grabbing her shoulder as she tried to look for cover. She can hear her partner shout her name, but she could also hear him struggling against a Beekeeper, who had the guts to engage him in a knife fight. 

Feeling a little recovered, she looked over her shoulder, and was met with a barrel of a rifle on her face.

She swallowed, her brain quickly trying to think of tricks to get out of the situation—

—a Beekeeper suddenly pushed the rifle away from her face, and Marinette was confused in an instant. 

_"Er sagte, "lebendig !""_

_What—_

She opened her mouth to speak, but was interrupted by the sound of gunshots. The two Beekeepers went down, and she sharply turned to her left. It was Gillet, looking very worried and pissed off at the same time.

"Gillet—"

"Call for backup. We're not going to win this, especially not in that state." 

He motioned at her shoulder, and she reluctantly nodded.

”HQ, this is Ladybug. We are currently surrounded with hostile forces, confirmed to be AIM soldiers. I repeat, AIM soldiers. Unit One and Two are down, I repeat, Unit One and Two are down. Request backup immediately!”

* * *

 "How many?"

"Don't do this to yourself _—"_

_"How many?"_

They were in the DGSE infirmary now, four hours after the back-up arrived and ended the battle. Most of her men were injured, some more damaged than the others. She was in the operating for an hour, and she wasn't able to find out the death toll before she was wheeled in. Somehow, the pain of the injury was nothing compared to the pain of seeing outcome of the assignment. 

The mercenary wasn't even there. The remaining Beekeepers even somehow managed to escape right off the bat. It was all a trap. 

And based on the magic-laced weapons and the puzzling statement from that one AIM soldier _—_

_—"Er sagte, "lebendig !""—_

It was all an elaborate trap to lure her in.

"It's not your fault, Cheng," Gillet, all bandaged up and recovered, continued to assure her gently, and Marinette's throat constricted as she fought back the onslaught of tears _because he had no idea._

Marinette once thought it's not possible to hate herself even more.

"These men knew the possible consequences when they signed up for this mission—"

"They wanted _me,_ Gillet. It was a trap for _me."_

Gillet paused, mouth still open from another attempt to cheer her up, "What do you mean?"

She looked at him with watery eyes. "It's all my fault."

 

**Author's Note:**

> *Casus belli = an act or situation provoking or justifying war.
> 
> This is an attempt on an ML/Civil War crossover. Any military jargon/term mistake I will eventually commit is all mine.


End file.
